1. Field of the Invention
The present invention relates to the field of distance traveled measuring odometers in general and in particular to that portion of the above noted field which is concerned with odometers that permanently indicate the fact that an odometer has been tampered with in an attempt to manually change the accumulated setting thereon.
2. Description of the Prior Art
In recent times, several attempts have been made to design odometers which are nonreversible or provide a visual indication to indicate that the accumulated value on the odometer has been reversed. In commonly assigned U.S. Pat. No. 3,801,005 (incorporated herein by reference), a particular construction of pinion gears and number wheels is disclosed which insures that if the gearing mechanism of the odometer is reversibly driven, the number wheels will not be lowered in their accumulated display value. However, such an odometer can be tampered with and the reading changed, for example, by using a sharp tool or pick to separate and disengage the number wheels from the pinion gears that are mounted on a somewhat bendable shaft. Upon separation, the number wheel may then be manually turned to a lower setting and thereby indicate a lower mileage on the vehicle than has actually been accumulated thereon.